What is the main operating unit in a centrifugal pump?

The impeller is the main operating unit in a centrifugal pump because it is the component responsible for transferring energy to the fluid being pumped. When the motor drives the impeller, it rotates and creates centrifugal force that propels the fluid outward from the center of the impeller. This movement lowers the pressure in the eye of the impeller, allowing fluid to be drawn into the pump from the inlet.

The design and size of the impeller directly influence the flow rate and pressure delivered by the pump, making it critical for the pump's performance. While the motor provides the necessary mechanical energy to drive the impeller and the housing contains and directs the flow of fluid, it is ultimately the impeller that achieves the primary function of moving the fluid through the system.

Valves, while important in controlling the flow within a pumping system, do not perform the primary pumping action. Thus, the impeller stands out as the key component defining the effectiveness of a centrifugal pump.